Jormungandar

or Midgardsormen (i.e. earth's monster). The great
serpent, brother of Hela and Fenrir (q.v.), and son of Loki, the
spirit of evil. It used to lie at the root of the celestial ash till
All-Fader cast it into the ocean; it then grew so large that in time
it encompassed the whole world, and was for ever biting its own tail.